User Guide

Table Of Contents

Chapter 3. General information and

proprietary Acronis technologies

3.1 The difference between file archives and disk/partition images

A backup archive is a file or a group of files (also called in this Guide “backups”), that

contains a copy of selected files/folders data or a copy of all information stored on selected

disks/partitions.

When you back up files and folders, only the data, along with the folder tree, are

compressed and stored.

Backing up disks and partitions is performed in a different way: Acronis True Image

Enterprise Server stores a sector-by-sector snapshot of the disk, which includes the

operating system, registry, drivers, software applications and data files, as well as system

areas hidden from the user. This procedure is called “creating a disk image,” and the

resulting backup archive is often called a disk/partition image.

Acronis True Image Enterprise Server stores only those hard disk parts that contain data (for

supported file systems). Further, it does not back up swap file information (pagefile.sys) and

hiberfil.sys (a file that keeps RAM contents when the computer goes into hibernation). This

reduces image size and speeds up image creation and restoration.

A partition image includes all files and folders independent of their attributes (including

hidden and system files), boot record, FAT (file allocation table), root and the zero track of

the hard disk with master boot record (MBR).

A disk image includes images of all disk partitions as well as the zero track with master boot

record (MBR).

By default, files in all Acronis True Image Enterprise Server archives have a “.tib” extension.

It is important to note that you can restore files and folders not only from file archives, but

from disk/partition images, too. To do so, mount the image as a virtual disk (see

Chapter 12.

Mounting an image as a virtual drive

) or start the image restoration and select Restore

specified files or folders.

3.2 Full, incremental and differential backups

Acronis True Image Enterprise Server can create full, incremental and differential backups.

A full backup contains all data at the moment of backup creation. It forms a base for

further incremental or differential backup or is used as a standalone archive. A full backup

has the shortest restore time as compared to incremental or differential ones.

An incremental backup file only contains data changed since the last full or incremental

backup creation. Therefore, it is smaller and takes less time to create. But as it doesn’t

contain all data, all the previous incremental backups and the initial full backup are required

for restoration.

Unlike incremental backup, when every backup procedure creates the next file in a “chain,” a

differential backup creates an independent file, containing all changes against the initial

full archive. Generally, a differential backup will be restored faster than an incremental one,

as it does not have to process through a long chain of previous backups.

A standalone full backup may be an optimal solution if you often roll back the system to the

initial state (like in a gaming club or Internet café, to undo changes made by the guests). In